Why does a motor or compressor need a capacitor to run properly? What actually does a capacitor do?

Question: Why does a motor or compressor need a capacitor to run properly? What actually does a capacitor do?

Answer: Thanks for your interest in our web site! Great question! You can get into a more complex answer for this question, but my heating and air conditioning teacher in vocational school explained it in the following way: On alternating current (AC) the current alternates on the voltage from zero to 110 or from zero to 220 volts 60 cycles per second. The run capacitor throws a stored charge in there when the voltage reaches the zero point and keeps the voltage steady instead of all the up and down voltage drops. This makes the motor or compressor run smoothly and more efficient. This is easily seen on an old oscilloscope where you can see the AC current going up and down. 60 cycles per second is pretty durn fast! It is amazing! I hope this answers your question. Hope you have a nice day! Sincerely, Steve Arnold